Acetaminophen (APAP) is the most common pharmaceutical product associated with drug toxicity. In severe cases, acetaminophen overdose may lead to acute liver failure (ALF) and death. Over 100,000 telephone calls concerning acetaminophen overdose are made to poison control centers in the U.S. annually. The FDA estimates that approximately 450 deaths are related to acetaminophen overdose annually. For patients that seek treatment within 24 hours of an acetaminophen overdose, and are able to provide accurate information regarding the time and amount of acetaminophen ingested, acetaminophen overdose is relatively straightforward to diagnose and treat. However, current methods of diagnosing acetaminophen overdose, such as the Rumack nomogram, are not very useful to diagnose patients after 24 hours of an acetaminophen overdose, when information regarding time and dose of acetaminophen ingested is not available, or patients that use alcohol, chronically ingest supratherapeutic doses of acetaminophen, or use sustained release acetaminophen formulations. Other laboratory tests, such as serum alanine aminotransferase (ALT) and serum aspartate aminotransferase (AST), indicate the occurrence of liver damage, but neither bioindicator is specific to acetaminophen overdose.
Accordingly, a need exists in the art for a method of accurately diagnosing acetaminophen-induced toxicity, including occult acetaminophen poisoning, even 24 hours or longer after the overdose.